JP-A-2012-88120 (PTL 1) describes a technique of reducing the mass of a lightweight section, by providing a concave portion in the lightweight section, in a physical quantity sensor of a seesaw structure including a heavyweight section and the lightweight section.
JP-A-2013-140148 (PTL 2) describes an acceleration sensor having a seesaw structure including a heavyweight section and a lightweight section, and a technique of reducing the mass of the lightweight section by providing an offset (step) in the lightweight section.